1. Field of the Invention
The present invention relates to nonvolatile semiconductor memory, and, more particularly, to a nonvolatile semiconductor memory device and a one-time programming control method thereof which do not need to perform an erase operation.
2. Description of Related Art
In general, nonvolatile semiconductor memory devices such as EEPROMs and flash memories perform a write operation, an erase operation, and a read operation. Of these, the erase operation is performed to write new data in the programmed memory cells.
Occasionally, designing a system using a nonvolatile semiconductor memory device involves setting and designing a one-time programming region on the nonvolatile semiconductor memory device. Data recorded in the one-time programming region is protected and can never be changed. The term “inherent data” will be used hereinafter to refer to data recorded in the one-time programming region. A nonvolatile memory cell array of the nonvolatile semiconductor memory device is divided into the one-time programming region and a normal region. The erase operation is designed such that it cannot be performed on data recorded in the one-time programming region.
New nonvolatile semiconductor memory devices such as ferro-electric RAM (FRAM), Phase-Change RAM (PRAM), and magnetic RAM (MRAM) do not need to perform an erase operation, and, thus, there is a need for a new method for maintaining data recorded in the one-time programming region.